Rectifier alarm system



Feb. 26, 1929. 1,703,146

W. H. T. HOLDEN RECTIFIER ALARM SYSTEM g n JNVENTOR W15( {CHQ/dew Wfi ATT ORNE Y Feb. 26, i929.

w. H. "r. HOLDEN REGTIFIER ALARM SYSTEM Filed May 5, 1924;

2 Sheets-Sheet 2 fag l INVENTOR WHZ/faf/ A TTORNEY Patented Feb. 26,1929.

UNITED STAT-Es PATENT oFFlcE.

'WILLIAM `H. T. HOLDEN, OF BROOKLYN, NEW YORK, ASSIGNOB T0 AMERICANTELEPHONE AND TELEGRAPH COMPANY, A CORPORATION OF NEW YORK.

BECTIFIER YALARM SYSTEM.

Application ma nay s, 1924. serial no. 711,302.

a storage battery, it is important that any' failure of the rectifyingdevice to properly -rectify the applied alternating voltage may beinstantly known.

It is the object of this invention to providey a method and means forinstantly indicating any failure of a rectifying device to properlyrectify the plate voltage..

Other objects of this mvention will be apparent from the followingdescription when read in connection with the attached drawing of whichFigure 1 shows the invention in its simplest form; Figs. 2, 3 and 4 showgraphically the principle of operation of the invention and Figs. 5 and6 show other forms of embodiment of the invention. In Fig. 1, a source 1of alternating voltage is adapted to be connected by means of certainblades of the single throw triple pole switch 2 with the primarywinding3 of the transformer 4. The secondary winding 5 of thistransformer which includes `all of the turns between the terminals 6 and7 is effec` tively connected across the electrodes of the rectifyingdevice 9. That portion of the winding 5 designated by 5" is used tofurnish the current necessary for heating the cathode 10 of therectifier. The battery 12, which is to be charged by the unidirectionalcurrent produced by the rectifying system, is connected between theanode 11 and the terminal 6 of the winding 5. A load 13 is connectedacross the terminals of the battery 12. Connected across the anode andcathode of the rectiier 9 is a marginal relay 14 in series with acontrolling resistance 15. This marginal relay, which is preferably ofthe slow release type, is intended to operate upon the margin existingbetween the voltage of the battery 12 and the average alternatingvoltage when the device 9 is properly rectifying.' The relay 16, whichoperates Whenever the switch 2 is closed and which is deenergized whenthe said switch is open, is intended i to prevent the continuousoperation of the alarm device 17 when the rectifier 9 is intentlonallystopped from operating.

The manner lin which this circuit operates to carry out the inventionwill be clearly understood from the foregoing description considered inconnection with the diagram! shown in Figs. 2, 3 and 4. Let it beassumed that the swltch 2 is closed, so that an alternating voltage willbe applied by the winding 3 to the windin 5. This alternating voltage 1srepresented 1n Fig. 2 by A. Since the battery 12 is in the same circuitas winding 5, the voltage across winding 5 will be superimposed upon thevoltage of the battery 12 represented by B of Fig. 2. If there were norec-y tifying device connected with the circuit, the resultant voltageapplied to the marginal' relay would have the form of the dotted waverepresented by C of Fig. 2. As is well known,

the superposltion of the alternating wave u on the direct currentvoltage results, in e ect, in a shifting of the zero axis of thealternating wave. For a symmetrical wave, the line representing theaverage value of successive half waves is, of course, the zero axis ofthe wave and this would coincide with the line representing the directcurrent voltage B. The proper operation of the rectifying device 9 inthe circuit causes unsymmetrica half waves, and the line representingthe average value of the alternating voltage wave will not coincide withthe line of the direct volta e. Thisdiference of voltage, represente bythe separation of the two lines, maintains the marginal relay operatedand thereby prevents the operation of the buzzer 17 bykeeping thecircuit of the latter open.

For a clearer understanding of this, consider that during the intervalaf-b of the voltage wave A, the terminal 8 of the winding 5 is positivewith respect to its terminal 6. With the battery 12 poled as shown inFig. 1, the alternating voltage during this half cycle will add to thedirect volta e, andA marginal relay 14. During the half cyclerepresented by the interval i-c, the alternatl. between the points o c.

ing voltage will oppose the direct voltage or the battery12, but thepolarity of the anode 11 will not become positive until the instant t isreached when the alternating voltageexactly equals the direct voltage.During the interval b c', the anode 11 will remain posif tive withrespect to its cathode vl0, and in .consequence thereof a flow otcurrent will take place across the gap of the rectifier 9, causing thevoltage across the electrodes to drop substantially to zero. 'lhis dropin the voltage is represented by the dot and dash line extending acrossthe trou h ot the wave C t the point ci the alternating and directvoltages again become equal, and thereafter the anode 11 is negativewith respect to its cathode so that further f current How through the'tube ceases.

llt the tube 9 is functioning properly, current will flow therethroughduring some part of every other half cycle, and during the inu terval inwhich such current dow taires place the voltage across the electrodeswill drop substantially to zero. As stated heretofore, the

voltage across the circuit including the marginal relay 14 is thevoltage across the electrodes oi the rectifier. When the tube isfunctioning properly, this volta e has the torni represented by the waveof ig. 3, and since the half waves are unsymmetrical with respect totheir zero axis, that is, the line which coincides with the linerepresenting the direct voltage B, the average value of successive halfwaves will not be represented by a line coinciding with the line B, butwill be displaced and may be represented by the line The marginal relay14 pulled up, so that the future control -of the lcircuit of the buzzer17 resides in the marginal relay. It the rectifier 9 fails to rectify,viz, current does not low between the electrodes during the interval bc', the voltage across these electrodes will therefore not dro to zero,.as represented by the dot and dash line, but it will be maintainedthroughout that portion o'f\the cycle as represented by the dotted line.Accordingly, the successive half waves of the curve C will besymmetrical with regard to their axis, which, as stated, coin cides withthe line B, and since the half waves are symmetrical, this linerepresents the average value of the successive half cycles. This meansthat the average value of the wave C coincides with the direct voltageB, and accordingly there is no margin of voltage to v is adjusted to beloperated at the voltage represented by D and and by 2in order todisconnect the sourcepf alternating voltage from the rectifying system,

the circuitoi` relay `16 will be opened, which,

in turn, will open the circuit of the buzzer 17 and discontinue thegiving oiD the alarm. The function of relayle is to prevent thel continuoustoperation of thebuzzerfduring thc time in which the rectifiernpurposely 'not operating. The coincidence or average 'voltage oli thewave C and ot the direct `voltage B is represented in vFig. 4f. Thearrangement show-n inlligl` 5', in which the saine reference charactershave been used to designate the same parts as shown in Fig. l, dierstrom that shown in Fig. 1 principally in the use of a diderential vrelayin place' `ofthe marginal relay shown yinllig. 1. 'The diqerential relay14V has one windinglS connected across the terminals of the battery 12.`Another winding 19, diiterentialwith' respect tothe first winding, isconnected'across the electrodes ofthe rectifier 9.v The remainder of thecircuit is substantially as shown in Fig. 1. This arrangement isintended to insure proper operation oi the alarm relay in case thebattery voltage increased, due to its being" charged, and thus cut down`the margin'between the direct current potential 'of the battery andtheaverage alternating voltage of the unsymme'trical wave, il e.,`thepartly rectilied wave. vBy the use of a device operating upon Vthedili'erential the diiiiculty arising from an increased battery voltagewould be avoided. Itis believed that the arrangement shown in Fig. 5 inwhich the alarm circuit is more sensitive to variationsin voltage,constitutes a more practicalforrn ofthe invention.

Fig. 6 shows the application of the invention to a mercury arc rectifierhaving a'cathf odev 20 and two anodes 21-and 2 2. These anodesareconnected with'these'condary 23 of the transformer 24, the primary 25of whichA is connected with a sourceof alternating p0- ,tentiaL The modeof connection is that well known in the art' for thel purpose ofobtaining llt? krectification of successive half waves. Con` P nectedbetween the anode 22 and the cathode 20 is a relay 26, and similarlyconnected'between the anode 21 and thecathode 2O is a relay 27, whichcontrols the alarm circuit.A Connected between the cathode 20 and themidpoint of the winding 23 is the battery 28 in series with thesustaining coil 29. A. work circuit 30 is shown connect-ed across thebattery 28. The manner in which this circuit operates is substantiallythat described in connection with Fig. 1. It the device is rectifyingproperly, the voltage between the anodes and the cathode will dropsubstantially to zero each anode and its cathode will be maintainedthroughout the half cycles in which rectification is supposed to takeplace, and accordingly there will be no marginof voltage to maintainoperated the relays 26 andl 27. Either or'hoth of these will bereleased, and the alarm will he set in operation.

While this invention has been disclosed as embodied in particular forms,it is to be understood that it is capable of embodiment in other anddifferent forms Without departing from the spirit and scope of theappended claims.

What is claimed is:

1. In a voltage rectifying'system, the combination with a voltagerectifier of a source of direct current potential connected therewith, asource of alternating potential adapted to superimpose its voltage uponthe said direct current voltage, and means responsive to the margin ofvoltage het-Ween the direct current voltage and the average of therectified alternating voltage to control the operation of an alarmsignal.

2. In a voltage rectitying system, the combination With a rectifier of asource of alternating voltage whose Wave is to he rectified, a source-ofdirect current voltage to be charged by the said rectified alternatingvoltage, and means responsive to the margin of voltage between the direct current voltage and the average of the rectified alternating voltageto control the operation of an alarm signal.

In testimony whereof, I have signed my name to this specification this2nd day of May, 1924.

WILLIAM' H. T. HOLDEN.

